Papillary muscles from the right ventricle of the cat were isolated in a chamber, and exposed to Ringer's solutions with different NaHCO3 concentration and pCO2, but with the same pH. When a Ringer solution containing 35 mM/1 and pCO2 40 mmHg was changed to another containing NaHCO3 80 mM/1 and pCO2 90 mmHg, a decrease in contractility, evidenced by a decrease in developed tension(DT) and rate of rise of the tension (dp/dt) without changes in the time to peak tension (TTP) was observed, in spite of the fact that pH reimained unchanged (7.40). It is concluded that extracellular pH is not a major determinant of the changes in myocardial contractility that follow acid base alterations.
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- Pharmacology, Toxicology and Pharmaceutics(all)